WARSAW (Reuters) - A huge cargo of elaborate marble stonework that sank to the bottom of Poland's Vistula river four centuries ago has re-appeared after a drought and record-low water levels revealed the masonry lying in the mud on the river bed.

Archaeologists believe the stonework was part of a trove which 17th-century Swedish invaders looted from Poland's rulers and loaded onto barges to transport home, only for the booty to go to the bottom when the vessels sank.